1. Field of the Invention
The present invention relates to the field of mechanical engineering, in particular of thermal machines. It concerns a method for cooling a thermally loaded component with a plate-type outer wall, in which method cooling air is supplied, in a first cooling section of the component, through a cooling air supply in the direction towards the outer wall and is deflected laterally in front of the outer wall and in a second cooling section is further guided parallel to the outer wall in a laterally adjoining cooling air duct for the purpose of further cooling.
Such a method for cooling the hot-gas casing and turbine inlet of a gas turbine is known, for example, from the German Offenlegungsschrift DE-A1 28 36 539.
The invention also concerns an appliance for carrying out the method.
2. Discussion of Background
In thermally loaded components of machines, for example the shells of the hot-gas casing and the turbine inlet for a gas turbine, cooling is frequently provided by means of cooling air. The cooling air then flows (FIG. 1) parallel to the outer wall 2 of the component 1, for the purpose of convective cooling, in a cooling air duct 3 along the outer wall 2. The cooling air duct 3 is, for example, formed by the outer wall 2 and a duct wall 6 in the form of a guide plate surrounding the outer wall 2 at a distance.
In the gas turbine, the cooling air usually originates from the compressor part and flows from the so-called plenum, which surrounds the hot-gas casing, into the cooling air duct 3. For this purpose, a gap-shaped opening is usually left free as the cooling air supply 5 between the duct wall 6 and the opposite boundary wall 4 at the inlet to the cooling air duct 3. The cooling air can enter the cooling air duct 3 through the cooling air supply 5. Because of the geometry present, the cooling air has, as a rule, a vertical velocity component in the region of the cooling air supply 5 so that the cooling air impinges, more or less strongly, on the outer wall 2 of the component 1 before entry into the cooling air duct 3 and is only subsequently deflected into the laterally outgoing cooling air duct 3.
The impingement results, on the one hand, in particularly effective impingement cooling on the outer wall 2 and, on the other hand, there is no cooling at all at the stagnation point of the incoming cooling air so that the component 1 is very inhomogeneously cooled in the first cooling section A in which this impingement cooling takes place. This inhomogeneous cooling causes additional and generally undesirable loads on the component.